Chisel retainer for chipping hammers



March 26, 1929. R. A. NORLING CHISEL RETAINER FOR CHIPPING HAMMERS Filed Sept. 11, 1924 Stb @atenta-sd Mar. 23, 1929.

ignara PATENT OFFICE.

.ii #OLD A. NORLING, OF AURORA.,

ILLINOIS, ASSIGNOR TO INDEPENDENT PNEU- EETIG lIOOII COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

CHISEL RETAINER FOR CHIPPING HAMMERS.

Application filed September ylhis invention relates to chisel retainers for pneumatic hammers.

The main object of my invention is to provide a retainer whereby relatively long chisels, such as employed in cutting cement .or masonry and in mine and quarry work, may he used with pneumatic hammers.

'In theaccom anying drawings- Fig. 1 is a si mer equipped with a chisel retainero my 1nvention;

Fig. 2 is an enlarged sectional view through the barrel and retainer;

lligs. 3 and 4 are vertical sectional views taken on lines 3-3 and 4-4, respectively, of lllig. 2;

Fig. 5 is a perspective View of one of the keys;

Fig. 6 is a view showing a stone drill used with the hammer; and

Fig. 7 is an enlarged vertical sectional vlew taken on line 7--7 of Fig. 6.

ln the drawings, 1 indicates the barrel of a neumatic chipping hammer In this type cip tool, the hammer piston 2 is prevented from being shot out of the barrel hy a bridge 3 projecting into the bore of the barrel ad] acent its front end. Attached 'to the forward or nozzle end of the barrel 1 is a chisel retainer of my invention.

The retainer includes an outer sleeve 4 in one piece of metal and fitting over the Jforward end of the barrel. Said sleeve 4 is held on the barrel by two dogs 5, 5 carried by a spring cli 6 on the outside of the sleeve The dogs phave inwardly extending prongs if 'l' ttin in grooves 8, 8 in the barrel, as shown ingFigs. 2 and 4. The ends of the prongs are rounded and so are the grooves, so that by twisting the sleeve 4, the dogs will work out of the ooves and the sleeve 4 can he pulled o the arrel end. p The end of the harrel is milled fiat on two sides to provide inclined surfaces a, a, so that in replacing the sleeve 4 on the barrel the dogs 5 carried therehy slide up on the barrel and spring into the grooves 8 when in register therewith. The sleeve has slots for the dogs to work through. 'This type of releasalole connection is the same as disclosed in the copending Axel Levedahl application, filed February 10, 1922, Sepial No. 535,624, patent 1,613,399, Jan. 4, 19

Sleeve 4 is relatively long and extends beyond the barrel 1 to some extent and has its e view of a pneumatic ham- 11, 1924. sensi No. 737,104.

ings 11, 11 to receive keys 12, 12, one in each 60 slot. Between shoulder 9 and inner sleeve 10 is an elastic bumper 0r cushion 13 made of rubber or other suitable resilient material. Surrounding the inner sleeve 10 at the keys 12 is a split sprlng ring 14. Said ring engages G5 the keys 12, 12 and holds them in place, that is, the ring keeps the keys from dropping out of their slots 11 when the inner sleeve 10 is out of the outer sleeve 4. Said ring 14 lies in registering grooves 15, 16 in the sleeve 10 70 and keys 12, respectively, so that the inner sleeve may fit within the outer one, as shown. The slots 11 are elongated lengthwise ci the inner sleeve 10 and the keys 12 have the same shape to fit in them; In the drawings, the U5 keys and slots have dat sides and ends so that the keys will not turn in their seats. in milling out the slots 11, a portion is left at their inner ends, as at Z) in Fig. 3, to prevent the keys 12 from dropping into the bore of @it the inner sleeve when the chisel shank 17 is withdrawn.

The inner ends of the keys 12 are rounded and engage the tool shank 17 in concave long the chisel shank so that the chisel may move endwiseunder a hlow thereon when struck by the hammer piston 2 during the operation of the tool. The inner ends of the grooves they ap roach the keys 12 as the chisel is driven orward, the keys exert a wedging effect on the chisel to retard its outward movement. The keys bearing against the bore of the outer sleeve 4 are held from movement out of the slots 11, and thus the outward movement of the chisel after the full eldest of the blow thereon has been utilized is gradually retarded, like appl ing a hrake, to prevent shooting the chise? out oi the sleeve 4. When this wedging action takes place, out ward movement of the inner sleeve 10 is cushioned b the rubber bum er 13. The action of the eys is substantial y the same as disclosed in said Levedahl application.

Equipped with my device, a pneumatic hammer may he used to cut out core sand in castings, cut up cement or masonry and for similar purposes. i

Tooves 18 therein. These grooves extend S5 18 are inclined outward, so that as so inner sleeve 10 `may be located in the outer sleeve beyond the barrel end, as shown. This provides a guide for the tool shank 17 in the sleeve 10, in addition to the guide provided by the bushing 19 in the barrel 1. This is an important feature of my invention for the reason that chisels used in this type of tool are often many feet long. The outer end of the retainer is not used as a guide because in practice chisel shanks are not iinished at that point and generally are neither concentric with the shank nor accurate in size. The bearing in the inner sleeve 10 is finished and concentric with the shank 17.

The retaining device being detachable, when removed from the barrel leaves hammer in normal condition, standard nozzle hole, etc. With my retainer, a shouldcrless chisel shank may be used. This allows the chisel to have its cutting end larger in diameter than its rear end, because the chisel need not be inserted into the retainer cutting end first. Thus the hammer may be used in mine and uarry work Ias a stone drill 17 n with its usual y large cutting end (Fig. 6) may be used with the hammer. With these drills their Shanks are hexagonal in shape and to accommodate them in the hammer its nozzle bushing 19't1 (Fig. 7) has a bore of the same shape. This prevents the drill from turning in the hammer' but is turned with the hammer in the drilling operation.

In assembling, the tool shank 17 is inserted rear end rst into the end of the retainer. Elastic cushion 13 is either placed in retainer or slipped over shank end after it is inserted. Chisel is then shoved through far enough into enlarged portion of outer sleeve 4, and inner sleeve 10 is then slipped over the shank. The spring ring 14 allows the keys 12 to expand until they find the grooves 18 in the chisel shank. The chisel 17 with inner sleeve 10 is then drawn into place in the outer sleeve 4, and the whole assembly slipped over the barrel end and twisted or turned until dogs 5 enter their grooves 8 and lock the parts on the barrel. The shank bushing 19 projects slightly beyond the barrel and the inner 'sleeve 10 has an annular recess 20 te receive it.

The outer sleeve 4 has the bore at its inner end enlarged to receive the barrel end with the latter against a shoulder c, as shown in Fig. 2.

The detailsbf structure shown and described may be variously changed and modified without departing from the spirit and scope of my invention.

l claim as my invention:

1. The combination with the barrel of a pneumatic hammer, of a chisel with its shank inserted in said barrel, a chisel retainer having elongated inner and out-er sleeves, the

latter being applied to the forward end of the barrel and extending beyond the same, a bushing in the forward end ofl the barrel,

said inner sleeve being entirely in front of the barrel and forming with said bushing a, guide and a support for the chisel shank, resilient means in the outer ysleeve and disposed to normally hold the inner sleeve against the barrel, and chisel shank retaining means carried by the inner sleeve and engaging the outer sleeve and held thereby in non-yielding engagement with the chisel shank.

2. The combination with the barrel of a pneumatic hammer, of a chisel with its shank inserted in said barrel, a chisel retainer having elongated inner and outer sleeves, the latter being a )plied to the forward end of the barrel an extending beyond the same, said outer sleeve having an inwardly extending shoulder at its forward end, a bushing in the forward end of the barrel, said inner sleeve being entirely in front of the barrel and forming with said bushing a guide and a support for the chisel shank, a rubber bumper in the outer sleeve and disposed between said shoulder and the inner sleeve for normally holding the latter against said barrel, and chisel shank retaining means carried by said inner sleeve and' engaging the outer sleeve and held thereby in non-yielding engagement with the chisel shank.

3. The combination with the barrel of a pneumatic hammer, of a chisel with its shank inserted in said barrel, a chisel retainer in-` cluding inner and outer sleeves, the latter being applied to the forward end of the barrel and extending beyond the same, said inner sleeve being in front of the barrel, cushion means in the outer sleeve and disposed to nor mally hold the inner sleeve against said barrel, and keys Carried by the inner sleeve and engaging the outer sleeve to be held thereby in non-yielding engagement with the chisel shank.

4. The combination with the barrel of a. pneumatic hammer, of a chisel with its shank inserted in said barrel, a chisel retainer including innner and outer sleeves, the latter being applied to the forward end of the barl rel and extending beyond the same, said inner sleeve being in front of the barrel, cushion means in the outer sleeve and dis osed to normally hold the inner sleeve against said barrel, keys carried by the inner sleeve and engaging the outer sleeve and held thereby in engagement with the chisel shank, and a. spring ring surrounding the inner sleeve within the outer sleeve and engaging said keys for holding the same in the inner sleeve, said inner sleeve and keys having grooves to receive the ring so that the inner sleeve may fit in the outer one.

5. The combination with the barrel of!!J pneumatic tool, of a chisel with its shank inserted in said barrel, a chisel retainer having inner and outer sleeves, the latter bein ap lied'to the forward end of the barre an extending beyond the same, said inner sleeve bein in front of said barrel and having fiat si ed slots extending therethrough beyond said barrel, flat sided keys in said slots and having their outer ends engaging the outer sleeve to be held thereby in engagement with the chisel shank, the latter havin rooves with inclined ends to receive sai eys and' gradually retard the outer movement of the shank under a blow thereon, and cushion means in the outer sleeve and disposed to normally hold the inner sleeve against said barrel.

6. The combination with the barrel of a pneumatic hammer, of a chisel with its shank inserted in said bairel, a chisel retainer including inner and outer sleeves, the latter being a plied to the forward end of said barrel an extending beyond thesame, said inner sleeve being in front-of said barrel and havin slots extending therethrough beyond saidarrel, cushion means in the outer sleeve and disposed to normally hold the inner sleeve against said barrel, and keys in said slots and held by the outer sleeve in en gagenient with the chisel shank, said slots havin inwardly extending portions to prevent t e keys from dro ping into the inner sleeve upon the remove of the chisel shank therefrom.

7. A chisel retainer havin inner and outer sleeves with the inner s eeve shorter than the outer sleeve and supported within the saine, said outer sleeve having an inwardin the inner sleeve.

8. The combination with the barrel of a neumatic hammer, of a chisel with its shank inserted in said barrel, a chisel retainer having elongated inner and outer sleeves, the latter being applied to the forward end of the barrel and extending beyond the same, a bushing in the forward end of the barrel and having a flat'sided bore to receive a like shiped chisel shank, said inner sleeve bein in ront of said barrel and forming with sai bushing a guide and a support for the shank, cushion means in the outer sleeve and disposed to normally hold the inner sleeve against said barrel, and keys carried by the inner sleeve and engaging the outer sleeve and held thereby in non-yielding engagement with the chisel shank.

In testimony that I claim the foregoing as my invention, I ax my signature this 5th day of Sept., 1924.

REINHOLD A. NORLING. 

